Trafalgar Square will be transformed into a giant reading festival in the summer, the Evening Standard reveals.

The free outdoor event will feature famous authors and celebrities reading on a big stage backed by an enormous interactive screen, with thousands of children following along.

Organised by the Evening Standard in partnership with e-reader firm NOOK, the July 13 Get Reading festival will allow children and their families to experience the magic of being transported by story in an iconic setting.

Kicking-off preparations for the unique, one-day read-a-thon, Boris Johnson read from The Wind In The Willows, by Kenneth Grahame, one of his favourite childhood books, to pupils at St Mary’s, our Get London Reading flagship primary school in Battersea.

The Mayor said: “I would like to see a London where kids are no longer illiterate at age 11. The target must be to stamp out illiteracy of 11-year-olds.

“I hope that Londoners embrace this wonderful festival and that as many as possible can make it to Trafalgar Square.”

Boris Johnson raced up to the gates of St Mary’s Primary School in Battersea today, parked his bike, and made for the library where he had an appointment to do a spot of reading.

“What’s your favourite book?” he asked the group of excited 10-year-olds trailing in his wake. “Harry Potter,” said one. “Harry Potter? Nah,” said the Mayor. “Come on, follow me, we’re going to read a real book.”

Perched on wobbly cushions, Mr Johnson read on a Nook eReader from The Wind in the Willows, by Kenneth Grahame, one of his favourite childhood books, he said. “It’s about a rat and mole,” he began. “My particular hero is a guy called Mr Toad. His family motto is ‘semper bufo’, which means ‘always a toad’. Mr Toad was a very keen motorist you see and also a Latinist.”

The Mayor was at St Mary’s, the flagship school for the London Evening Standard’s Get London Reading campaign, to kick off preparations for the giant one-day reading festival, to be held in Trafalgar Square on July 13.

Announced today, the one-day “Get Reading” event will feature famous authors and celebrities reading on a big stage backed by an enormous interactive screen, with thousands of schoolchildren following along, and it will be free to the public. It has been organised by the Standard in partnership with NOOK, a subsidiary of the US bookseller Barnes & Noble.

The Mayor said: “What the Standard is doing is fantastic. This is a great campaign. The Mayor’s Fund has backed the paper’s literacy campaign with quite a lot of dosh, £500,000 to be precise, to help put reading volunteers into wonderful schools like this, and now NOOK have stepped in to help sponsor this reading festival and donated 1,000 Nooks to the volunteers.

“I would like to see a London where kids are no longer illiterate at age 11. The target must be to stamp out illiteracy of 11-year-olds, and this is where the Standard’s literacy campaign has done such pioneering work. Think of the potential — almost one in five kids is leaving primary school unable to read or write — think of what they would go on to achieve, think of the economic benefits that would bring to London, if we could turn that round and turn these kids on to reading.

“I hope as many Londoners as possible can make it to Trafalgar Square for the giant read-a-thon packed full of literacy-boosting activities and famous book lovers.”

Mr Johnson was followed on to the “reading cushion” by Evgeny Lebedev, owner of the London Evening Standard and The Independent, who read from Oscar Wilde’s The Selfish Giant. “I was terrified to read in front of my classmates when I was your age,” he told the children. “I hope today to overcome that fear.”

Mr Lebedev added: “As the enthusiasm of the children this morning shows, reading has opened their lives to the wonderful stories that only books can bring. The Trafalgar Square read-a-thon will be a celebration of all that our literacy campaign has achieved and promises to be fantastic fun!”

Jim Hilt, managing director of Barnes & Noble, owners of NOOK, said: “This festival is going to be a celebration of books, creating excitement around our favourite children’s stories. We came to the UK to be a part of the fabric of community by creating affordable access to reading and we believe that this festival will further the campaign.”

St Mary’s executive headteacher Jared Brading encouraged the children to vote by hand on which book they preferred as the Mayor scratched his head over the workings of his eReader and asked a 10-year-old to help him.

Mr Brading said: “We will definitely be taking our pupils to the festival. It will be a wonderful opportunity to combine reading with a great day out.”

Barnes & Noble pledged last month to donate 1,000 Nook eReaders to our literacy campaign. A number of leading publishers — including Hachette, HarperCollins, Penguin and Random House — have agreed to donate books such as Mr Stink, Charlie and the Chocolate Factory, and Ruby the Red Fairy for the eReaders.

Get London Reading, launched two years ago to help struggling readers, has so far raised £1 million, including £500,000 from the Mayor’s Fund for London. The cash supports almost 700 reading volunteers trained by our campaign partners Beanstalk to help more than 2,000 children at hundreds of London primary schools.

More details on the line-up for the Trafalgar Square festival — to be held on Saturday, 13 July from 11am to 5pm — and on how the public can register will be revealed shortly.